Seeking Software.

[Chris]

I'd like to get a software package that can do the following:

Input the ballistic data of a particular round and the configuration of a firearm.

Get back 3 numbers:

Effective range so that in no part of the trajectory will the bullet be more than say 3 or 4" above or below the sight line

Close Zero (ie. the point where the flight path first crosses the line of sight.)

Range Zero (ie. the point where the flight path crosses the line of sight the last time.)

I'd like the entry data to be as complete as possible, but no so complex that I can't get a usable answer if I'm missing minor details.

I know that the height of the sights, the muzzle velocity, grain size of the projectile, drag coefficent, and other stuff will all be needed.

Basically, I'd like to be able to set real useful zeros for my rifles and longer range handguns to maximize their effective range in relation to the sights. And, have some idea as to what that range would be.

 

[jhrosier]

This spreadsheet should do what you need:

http://accurateshooter.net/Downloads/pejsajacksonballistics.xls

Jack

 

[Prepper]

I was wondering about such software too. I took a look at that spreadsheet, but quickly realized I'll need to learn a whole lot more about the subject before I can make use of that.

I really need some kind of "Ballistics for Dummies" book. Although, I do see the risk of encouraging dummies to use guns, but it'd still be a nice book to have if it existed.

 

[jhrosier]

Balistics for dummies: http://www.rifleshootermag.com/shooting_tips/ballistics_0303/

More info: http://en.wikipedia.org/wiki/External_ballistics

You could also look at a loading manual. The Lyman 46th Ed has a good article. There are many resources on the net, if you are willing to put out the effort to learn.

BTW, the Excel "GoalSeek" function can extend the use of the previously mentioned spreadsheet to find the first zero crossing by backsolving for the "special range", using a zero value for the bullet path. The MRT can be found by solving the path column for the max value. The max value cell can be used to backsolve the sighting in distance for a specified maximum path value. Then you can solve the special range cell to show the range that the bullet will fall below zero by the MRT. Hint, preset the special range to a greater value than the sight in distance befoe trying this.

Try creating a chart on the gunstock table tab to show the path at each range.

If you use the muzzle velocity and the velocity at a given range from the manufacturer's data for a factory load, you should be able to use "goalseek" to find the effective B.C. for the factory load and generate a trajectory chart for any range and sight setting.

The possibilities are nearly endless.

None of this is rocket science and the help functions in Excel will guide you through using the functions.
You should be able to get the Balistic Coefficient for most any bullet from the manufacturer's website, or most handloading manuals.

Jack

 

[bpm990d]

JBM Small Arms Ballistics is free and very good. They have a list of freeware you can download and he also programmed a pretty good calculator (webware) on the page.

B